The present invention relates to loading assemblies used for testing portions of a vehicle. More particularly, the present invention relates to a loading assembly for applying selected forces and moments to a vehicle spindle, the loading assembly being adaptable to various vehicle suspensions.
Many test fixtures have been advanced to apply forces and moments to a vehicle spindle in order to simulate driving or road conditions. These test fixtures often include separate actuators to apply vertical, longitudinal and lateral forces as well as braking moments to the vehicle spindle. U.S. Pat. Nos. 4,733,558 and 5,083,453 disclose two such test fixtures.
Commonly, the test fixtures include a wheel adapter housing that is mounted to the vehicle spindle in place of a wheel and tire assembly. Two vertical struts are joined to the perimeter of the wheel adapter housing and are used to transfer the longitudinal forces, the vertical forces and the braking moments to the vehicle spindle. A center downwardly projecting tang located between the vertical struts and also rigidly joined to the perimeter of the wheel adapter housing is joined to a lateral strut. An actuator is joined to the lateral strut and applies loads to the vehicle spindle that are generally perpendicular to the vertical struts.
Although the above-identified test fixtures are quite capable of applying longitudinal forces, vertical forces, lateral forces and braking moments to the vehicle spindle, some crosstalk which is the application of an unintended force in one direction through the application of an intended force in another direction exists. For example, when a lateral load is applied to the wheel adapter housing while the wheel adapter housing undergoes displacement about the vehicle spindle axis, an unintended braking moment is also developed. Similarly, an unintended longitudinal force is developed when a lateral load is applied to the wheel adapter housing with longitudinal displacement of the wheel adapter housing.